Various speaker systems have been designed in the past to handle a wide range of acoustic needs. For example, when high-fidelity sound reproduction is not critical, a speaker may be designed with only one audio driver or speaker cone so that all of the high, midrange and low audio frequencies are handled by the single speaker. Unfortunately, single cone speakers, referred to as wide range speakers, tend to exhibit some distortion since a small speaker cone will generally handle high frequencies well, while a large speaker cone is typically better suited to handle the lower frequencies. Thus, a wide range speaker is generally not well adapted to reproduce the full frequency spectrum of audio information with high-fidelity. Rather, the higher or lower frequency range is reproduced with more quality as a function of the speaker cone size.
To overcome this problem, high-fidelity speakers are designed to include two or more speaker cones in the speaker. In a two-way speaker, for example, a small tweeter reproduces the high frequencies, and a relatively large woofer handles the low frequencies. In a three-way speaker, a third or midrange speaker cone is added to improve coverage of middle frequencies between the highs of the tweeter and the lows of the woofer. A crossover network or special filtering circuit is generally used to separate the audio signal frequencies and feed them to the appropriate high, low or midrange audio driver in the speaker.
Additionally, depending on the specific acoustic needs of the listener, one, two or four speakers may be required to reproduce the desired audio program. For example, when high-fidelity sound reproduction is desired from both right and left channel audio signals of a stereo system, two speakers are connected to the stereo system to produce a true stereo acoustic environment. In particular, a true stereo system uses two independent speakers with each speaker reproducing one or the other of the right and left channel audio information. In this way, right channel audio information is reproduced by one speaker along a right audio axis while left channel audio information is reproduced by the other speaker along a left audio axis to produce a true stereo effect to the listener.
In some rooms however, such as in a confined bathroom or attic for example, it may be difficult to use two independent speakers to reproduce the right and left channel audio information. In such cases, a single speaker may be used which is connected to only one of the right or left audio channels of the audio source. Thus, while the single speaker is able to reproduce sound within the room, the reproduced audio program is less than ideal as the audio information from one or the other of the right and left audio channels is missing entirely from the audio program.
To address this problem, dual voice coil speakers have recently been developed that include a single speaker cone with a pair of independent voice coils to drive the single cone. The dual voice coil speaker is designed so that both of the right channel and left channel audio signals are handled separately by the independent voice coils so that none of the audio information is discarded or sacrificed by the speaker. The right and left channel audio signals are mixed within the single speaker so that right and left channel audio programs are simultaneously reproduced by the single speaker. Unfortunately, however, dual voice coil speakers suffer from the same drawbacks of any wide range speaker in that the single speaker cone is not well suited to reproduce all of the frequencies very well. Thus, while all of the right and left channel audio information is simultaneously reproduced by the single speaker, the reproduced audio program is considerably less than high-fidelity. Moreover, dual voice coil speakers are designed only for mixing right and left channel audio signals, and their design prohibits them from being used in a true stereo environment in which two speakers are connected to an audio source to independently reproduce the right and left audio information. Thus, dual voice coil speakers generally have a very limited application to single speaker acoustic environments.
Thus, there is a need for a speaker system that is well suited to handle a wide range of audio frequencies and reproduce an audio program with high-fidelity. There is also a need for a speaker system that reproduces an audio program without significant distortion or loss of audio information. There is also a need for a speaker system that is versatile for use in a wide range of acoustic environments in which a single or multiple speakers may be required.